Machine tool



MACHlNE TOOL Application May 3, 1954, Serial No. 427,235 Claims priority, applicationswitzerland May 4, 1953 4 claims. (C1. 9013.s)

The present invention relates to a machine tool of the type described and illustrated in my copending application Serial No. 319,646 tiled November 10,1952, having a longitudinal table moved by means of a mechanical feed device and a hydraulic copying device comprising a cross slide moved along a linear jig, a differential gear being interconnected in the mechanical longitudinal feed device, said gear being connected with a regulating unit controlled by the hydraulic copying device in such a way that the speed of the longitudinal feed is regulated in dependence of the longitudinal linear jig.

According to the present invention a pilot-control member is provided, which co-operates with the jig in additiontothe feeler' member of the hydraulic copying device, and which, at steep portions of the jig, acts upon an auxiliary control piston by means of which a slowing down of the longitudinal feed is produced previous to the response of the hydraulic copying device to the change of direction of the jig. This provides a substantial `improvement for the precision of the copying operation.

Other objects and advantages of the invention will become apparent from the description now to follow, of a preferred embodiment thereof, and in which reference will be had to the accompanying drawings, in which:

Fig. l shows a diagrammatic view, partly in section, of a horizontal milling machine.

Fig. 2 is a longitudinal section through the feeler head and the additional control piston, at enlarged scale,V and Fig. 3 is a side view of the jig, of the feeler roll and the pilot-control member.

In the embodiment illustrated in the drawings the table 3 is longitudinally guided on the machine bed 1- in a guiding 2. A milling spindle box 5, with a coupled milling cone 6 and guiding slide 7, is vertically guidedi. e. transversely to the direction of feed of the table 3-on supports 4. A piston rod 8 bearing a piston 9 cooperating with a cylinder 10 is fixed to the lower portion of the milling box 5. Conduits 63 and 64 coming from a maincontrol cylinder 65 are connected to the cylnder 10. Conduit 66 connects the oil pump 67 with the control cylinder 65. Branch conduit 68 connects over a governor valve 69 the conduit 66 with the oil tank 70. Within the main control cylinder 65 there is provided a main slide valve 103 spring-loaded at one end by a spring 194. The latter acts with its other end against a slide valve 105 provided with a ball socket 106 cooperating by means of a ball 107 with the end of an arm for the feeler roll 108. By means of a ball 109 this arm 108 is arranged in the cylinder 65 so as to be movable in all directions and it carries at its right-hand end a feeler roll 22 cooperating with a linear copying jig 23 secured to the table 3. Two annular grooves 72, 73 connected with'the conduits 63, 64-are provided in the control cylinder 65. Control edges 74, 75, 76, 77 of the control slide valve 103 cooperate with this pair of annular grooves 72, 73. The slide valve 103 furtherpcomy prises openings 78, 79 and a bore 80 for the return iiow nited States Patenti i ,j 2,767,621 Iiiattented Oct. 23, 1956 of the pressure uid. A return [conduit 81 connected with the bore leads from the control cylinder 65 to a container 70 containing the oil pump 67 and a sump 82. Conduit 98 with the two) branch vconduits 99 and 100 provides the control cylinder 65 with oil from the oil pump 67. Control `edgesA 85. and 86 cooperate with the annular grooves 83V and .84 of the control cylinder 65, which control edges have a connection with Vthe annular groove 87 itself connected .witha conduit 88 leading to an auxiliary control cylinder 89.I The rcontrol edge 90 of the control slide valve.91 cooperates with an annular groove 92 in the control cylinder..89 and permits back flow of the oil through a return conduit 93 to the container 70. In addition to the feeler ro1l.22 there is a pilot-control disc cooperating withV the copying jig 23, whereby the diameter of this disc is superior to a predetermined value to the one of the actual Ycopying feeler roll 22. The. disc 110 isz-connected to a pilotcontrol rocking frame 111 pivotally mounted on the cylinder 65 by means of a pivot 112 and in addition thereto supported by a guiding key'113. The rocking frame 111 is provided at its upper end with a ball socket 114 into which the hemispherical end of an additional control piston 115 is pressed under the action of a spring 116. This piston 115 is arranged'in a block 117, having a control edge 118 cooperating with this piston 115, and to which are connected two conduits 119, 120, the first one being connected with conduit 98 and thus with the oil pump 67 and'the second 120 with conduit 88 leadingto'y the auxiliarycontrol cylinder 89. A governor valve 121 is interconnected into this second conduit 120 for regulating the oil stream. l f

A feeding conduit 94 connects the sump 82 with the regulating unit 42 being in the, present, case a toothedwheel oil pump. This oil pump and the planetary diierential gear associated, therewith are constructed as described in my copending application Serial No. 319,646 filed November 10, k1952. QA spur wheel 54 of this gear is mounted on the shafts SS-ofa driving motor 56. A further spur wheelv57, engages a spur wheel 58 driving overa change yspeedgear` 59 and bevel wheels 60 the feed 61 of the table. p

Y The described machine tool operates as follows:

As the feeler roll arm 108 is in its neutral middle position, the control yslidevalve 103 in Fig. 2 is in a position, in which it is somewhat displaced tothe right with respect to the representedv middle position. In this position of the control slide valve 103 pressure iluid isrfed from the conduit 68 over the-control edge 76 into the annular groove 73 and through, conduit 64 into the room of the cylinder 10 below the piston 9, while the room above the piston 9 is connected tothe sump through conduit 63, control edge 74,-ope'ning 78, boring 80 and conduit 81. The piston` moves upwardly thereby entraining Vthe milling spindle box 5 and the milling cone 6. When the feeler roll 22 co-operates with the jig 23 the feeler roll arm 1.08 is moved out of its neutral middle position. Thereby, owing to the action of ball 107 onto the ballsocket'106the slide valve 105 and thus the controll slidefvalve 103l are axially moved to the left, free from play, against the action of spring 104.v When the'control slide valve 103 has displaced itself to such an extent that itis in the neutral middle position Ashown in Figs. `l and. 2, the piston 9 and thus the milling spindle box 5. andthe milling cone 6 stand still.

Thus a determinated swinging-of the feeler-roll arm 108 corresponds to'this neutral position-of the control slide valve 103,.Upon further-` movement `the control slide valve 103 is movedto the left out'offthe neutral middle position of Fig4. 2,- Therebypressure' fluid is fed to the room 'of the'cylinde'rlll above :the piston 9 through conduit 68 over the control edge 75; annular groove 72 and conduit 63, while the' roomA `of `the cylinder 10 belowA the piston 9 is connected to the sump 82-through conduit 64, lcontrol edge 77, opening 79, boring 80 and conduit 81. The piston is` controlled insucli a Way that the milling spindle -box with the millingfcone 6 move downwardly.` j Y ln the neutral middleposition'of thecontrol slide valve 103 and of the controliedgesSS, 86 respectively, passage of pressure fluid from conduit 98j`and annular groove 83, 84 respectively, to `the annular groove 87 and feeding conduit 8S to the second control cylinder 89 is impossible. Thus no pressure fluid can' 'owfthrough conduit 88 and i the jig 23 onto `the feeler roll 22,

movement of the table, a differential gear interconnected no axial displacement is` imparted to the auxiliary coni trol slide valve 91: 'Moreover this results in the ,control edge 95 remaining closed' and'rendering impossible passage of pressure fluid Vfrom the annular groove 96 into the return conduit 93' so thatthe pump 42 is not actuated. The shaft 46 does not rotate so that the rotation transniitted'from the shaft 55 `of the motor 56 over the wheel 54 to the planet wheel carrier 50 is transmitted to the shaft 52 over theplanet wheels 48, 49 engaging each other and the sun wheels 47, 51. Thereby the planet wheels 48 turn around the sun wheel 47. The table 3 `is moved at maximum speed by the shaft 52 over the toothed wheels 57, 58, the change speed gear 59, the bevel wheels 60 and the slide drive 61.

When at flat portions of thejigthe co-operation of the feeler roll 22 with the jig 23 `produces a swingingI of the feeler arm 108, the `control slide `valve 103 is axially moved owing to the action of the ball 107 onto the ball socket 106, as already mentioned and the milling spindle box 5 is vertically displaced as already described.` The control cylinder 65 Lis mechanically connected with the milling spindle box 5 byrneans of a rggingf62 `so that the necessary back action is guaranteed. Upon displacement of the' main control slide valve 103 out of the illustratedY 'neutral middle position the mentioned passage between the conduits 98 and 88 `is `opened at one of the control edges, 85', 8,6 so `that now pressurefluid may ow through conduit`88 and reach the auxiliary control slide valve 91`. According' to .the passing quantity of oil the auxiliarycontrol' slide valve 91 is axially shifted against the action` offa spring 9,7 so that the control edge 95 opens the passage tothe conduit 101 and the pump 42 can rotate. The rotation ofthe shaft 55 of the motor 56 transmitted over.` the toothed wheel 54 to the planet wheel carrier 50 is now partly transmitted `to shaft 46 of the pump 42 and partly over shaft .52 to the table drive 61.1 It results therefrom a rotation of the table 3 at `reduced speed whereby thisspeed depends on the quantity `of fluid raised 'by the pump 42 through the passage in the control slider valve 91.

The afore-described operation takes place when the jig is flat or has a small upward or downward slope, whereby the jig co-operates directly with thefeeler roll 22 in the attened upperregion ofthe pilot-control disc the one for example `shown in Fig.l 3, the jig, previously to its influencing `the feeler roll 22 acts upon the pilotcontrol disc 110. Thereby the pilot-control rocking frame 111 is swung about the pin 112. `The auxiliary control piston 115. pressed ,into` the ball socket 114 by the spring 116 is axially displaced. to the leftl against the spring action and opens the,V control edge 118 of the block 117. Thereby an oil"`circulation is formed from pump 67 over the conduits 98 and 119, block 117conduits 120 and 88 `to the auxiliary control slide valve 89 and back from the latter through conduit 93 to the sump 82. Thepassage of oil' through conduit 120 may be adjusted by the governor valve 121.` The, auxiliary control slide `valve.91V is displaced to the right by the in said mechanical feed device, a regulating unit connected to said differential gear for changing the `speed of the longitudinal feed, a working piston for transverse movement of said cross slide, a hydraulic `copying device for controlling the said cross slide, including a hydraulic control slide valve, a feeler and a longitudinally linear jig engaging the feeler, a pilot-control member coi operating with said jig in addition to said feeler and an additional control piston associated with said pilot ,con-

oil pressurefresulting in the already described slowing down of the tablemovernenf previous to the action of trol member and cooperating therewith at steep portions of the jig, and a connection between said additional control piston and said regulating unit for controlling said regulation unit in response to said pilot control merriber for slowing down the longitudinal feed at steep portions of the jig previous to the response of the said hydraulic copying device to the change of direction of the jig.

2. ln a machine t-ool having a longitudinal movable table and a transversely movable cross slide, the combination comprising a mechanical feed device for longitudinal movement of the table, a differential gear interconnected in said meclianicalfeed device, a regulating unit connected to said differential gear for changing the speed of the longitudinal feed, a working piston for transverse movement of said cross slide, a hydraulic copying device for controlling the said cross slide, including a hydraulic control` slide valve, a feeler and a longitudinally linear jig engaging the feeler, a pilot-control member cooperating with said jig in addition to said feeler and an additional control piston associated with said pilot control member and cooperating therewith at steep portions of the jig, an auxiliary control slide valve associated with said additional control piston so as to be actuated by the latter previous to its actuation by the main control slide valve, and a `connection between said auxiliary control slide valve and said regulating unit for controlling said regulation unit in response to said pilot control member for slowing down the longitudinal feed at steep portions of the jig previous to the response of the said hydraulic copying device to the change of direction of the jig.

3. In a machine tool having a longitudinal movable table and a transversely movable cross slide, the combination comprising a mechanical feed device for longitudinal movement ofthe table, a differential gear interconnected in said mechanical feed device,` a regulating unit con nected to said differential gear for changing the speed of the longitudinal feed, a working piston for transverse movement of said cross slide, a h draulic co in device only. For steeply inclined jig portions, however, as y py g for controlling the said cross slide, including a hydraulic control slide valve, a feeler and a longitudinally linear jig engaging the feeler, a pilot-control member cooperating with said jig in addition to said feeler, a pilot control rocking frame carrying said pilot control member, an additional control piston associated with said pilot control rocking frame so that a swinging of said rocking frame results in a shifting of said auxiliary control piston, and a` connection between `said `additional control piston and said regulating unit for controlling said regulation unit in response to said pilot control member for slowing down the longitudinal feed at steep portions of the jig previous to the response of the said hydraulic copying device to the change oftdirection of the jig.

4. In a-machine tool having a longitudinal movable table and a transversely movable cross slide, the combination comprising a mechanical feed device for longitudinal movement of the table, a differential gear interconnected in said mechanical feed device, a regulating unit connected to said differential gear for changing the speed of the longitudinal feed, a working piston for transverse movement of said cross slide, a hydraulic copying device for controlling the said cross slide, including a hydraulic control slide valve, a feeler and a longitudinally linear jig engaging the feeler, a pilot-control member cooperating with said jig in addition to said feeler, said pilot control member formed as a circular disc arranged concentrically to said feeler and having a diameter greater than the said feeler and being provided with a attened portion on its side directed towards the jig, a pilot control rocking frame carrying said pilot control member, an

additional control piston associated with said pilot conl5 2641969 trol rocking frame so that a swinging of said rocking frame results in a shifting of said auxiliary control piston, and a connection between said additional control piston and said regulating unit for controlling said regulation unit in response to said pilot control member for slowing down the longitudinal feed at steep portions -of the jig previous to the response of the said hydraulic copying device to the change of direction of the jig.

References Cited inthe le of this patent UNITED STATES PATENTS 2,330,890 Horlacher Oct. 5, 1943 2,391,492 Turchan et al Dec. 25, 1945 Roehm June 16, 1953 

